Centrifugal hammer



May 24, 1927 GI P LUCAS CENTRIFUGAL HAMMER Filed Aug. 1, 1924 I NEY Patented May 24, 1927.

UNITED STATES,

I 1530,021' PATENT OFFICE.

GEORGE P. LUCAS, OF JERSEY CITY, NEW JERSEY.

cnnrmruear. AMMER.

Application filed August 1, 1924. Serial No. 729,464.

This invention relates to hammers. More particularly, the invention is directed to improved means of the construction and assembly of reversible tips for hammers, and especially of the centrifugal type.

My invention is applicable to hammers of mills and other machines for breaking-up,

my invention, each hammer comprises a shank portion having at one end suitable means for pivotal suspension from a suspending shaft or the like and provided at its impact end. with .a tip of preferably highly hardened material such as manganese steel and reversibly mounted thereon by I means of a.dove-ta11 or like connection affording reversal of the effective ends of the tip. The impact end of the shank is cut away to receive in a substantially rigid manner the end of the tip not in effective use and also in a manner to coact with the dove-tail groove whereby the strains to which the tip as a whole is subjected, are distributed to relieve the dove-tail joint from undue strain.

Further features and objects of the invention will be more fully understood from the following detail description and the accompanying drawings, in which Fig. 1 is a side elevation of ahammer for a centrifugal mill embodying my invention;

2 is a detail top plan View of the impact end of the shank and the tip mounted thereon;

' Fig. 3 is a front end elevation of Fig. 1; Fig. 4 is a sectional elevation on line 44 of Fig. 2';

Fig. 5 is a top perspective view of the tip proper; H

Fig(.16 is a detail bottom plan view of Fig. an

Fig. 7 is a central sectional elevation simi- Iar to Fig. 4 but showing a modification.

Referring to Figs. 1 to 6, inclusive, the hammer comprises the shank portion 10'having at one end the opening 11 for pivotal suspension from a suspending shaft ort-he like; it will be understood that the manner of suspension of the hammer may be varied as desired. I

The front or impact end 12 of the shank 10 is preferably enlarged by greater width to form ahead, as indicated in- Fig. 2, to thereby increase theefiective momentum. The lower fro-ntportion13, seeFig. 1, of the impact end 12 is cut away as-indicated to form a preferably symmetrically re-entrant groove 14 for receiving the or like head 15 of the tip 16. The ti 16, see Fig. 5', is preferably fiat on its lower face dove-tail I 17 and is cut away slantingly at a slight angle at its upper faces 18, 19 respectively on the opposite sides of the dove-tail head 15. The opposite ends 20, 21 of the tip 16 are preferably flat and substantially at right angles to the lower face 17.

The impact end 12 of the 'shank.10 is preferably sloped on its lower face portions 22, 23, see Fig. 1, corresponding to the angles of slantof the upper face portions 18, 19, of the tip 16, to provide for-substantially face to face engagement respectively between the face portions 22, 23 of the shank head 12 and the face portions 18, 19 -of'the tip 16.

Proximate and belowjthe re-entrants slot 14 of the head 12 of the shank .10, I provide the recess 24 open at its front, formed by the extension 25, preferably integral with the body portion of the head 12 of the shank 10; the extension 25 preferably tapers toward the tip 16. The upper and forward end portion 26 of the head 12 is preferably curved and terminates within the outer or effective end of the ti 16 to thereby provide for, the projection o the effective end, say the end 20, see Figs. 1 and 3, forwardly of'the forward end 26 of the head 12 of the shank 10. It will be noted that the tip 16 preferably extends laterally-on both sides beyond the head 12. y I

In assembling, the tip 16 is slipped into position in thehead 12 by registering its head 15 withinthe groove 14 and its unused end, say 21,'within"the recess 24. For fur ther securement-of the tip 16 in the head 12' of the shank 10, the pin 27 is received in the opening 28 through .the tip 16 and the opening 29 in the head 12 and preferably locked by means of a cotter pin 30. The head'3l ofthe pin 27 is preferably countersunk and the upper side, 32 of the head 12 tip 16 is provided with a T-head fitting within a corresponding groove 36 in the shank head 12. The parts of Figs. 7 corresponding to the parts shown in Figs. 1 to 6, inclusive, are designated by like reference numbers. h

Fig. 7 also shows the modification of the pin 37 having a threaded end 38 for receiving the nut 39, which when tightened 1s enclosed within the recess 40 in the upper slde 32 of the head 12.

Up'on inserting a new tip within the head of the shank, the exposed end of the tip 16, say the end 20, is the effective area of impact with the material to be broken-up or comminuted. The opposite end, say the end 21, see Figs. 1, 4 and 5 is protected within the recess 24. The form of the joint between the tip 16 and the head 12 serves to distribute substantially uniformly the strains to which the tip is subjected by the impact on the materials acted upon. The area of face to face contact between the head and the tip is increased by reason of the provislon of the recess 24, whereby the wear on the contacting surfaces of the groove 14 and the groove 24. is minimized, thus prolonging the life of the shank of my hammer.

When the exposed or effectively disposed end tip has been worn, the tip is removed from the head and reversed. Upon wear of both tip ends, a new tip is positioned withm the head. I

The shank may be formed of steel or other material capable of being cast or dropforged in finished form. It will be noted that the groove 1 and the groove 24 are presented on an open face of the shank head 12 to afford ready access for grinding or other finishing if desired. The tip 16, as indicated hereinabove, is preferably of highly refractory material such as manganese steel or the like which is cast to final form.

My invention is highly advantageous for hammer mills, in that substantially the entire wear ofthe hammer is taken up by the tips. Each tip is readily replaced by mere reversal of the tip in the respective heads without disturbing its shank or the shanks or tips of other hammers. It will. be noted that the extension of the enlarged head at an angle on one side to the direction of.

' gravity and advances the tip. Such arrange ment also minimizes any difference in balance of the combined shank and 'tiparising from the non-effective tip portion on the tip portion enclosed in the recess 24 being of essened weight due to wear, thereby obviating any necessity of compensation or adjustment of waitlng of the hammers on the respective suspension shafts of the mill or other machine.

The head 15 of the tip may be tapered at its lateral faces 15*, 15 as indicated in Figs. 2 and 5.

Whereas I have described my invention by reference to specific forms thereof, it will be understood that many changes and modifications may be made without departing from the spirit of the invention.

I claim:

1. A hammer for a centrifugal mill comprising a shank portion provided at one end with an opening for suspension, the opposite end of said shank being enlarged in at least two dimensions, said enlarged end portion having a recess bounded on its opposite faces by wedge-shaped walls, the median line of said recess extending transversely to the direction of length of said shank and a tip member comprising a body portion extending at its oppositely disposed ends to serve as tips and further comprising a wedge-shaped extension on one Side of said body portion and disposed symmetrically relative to said tips, said wedge-shaped extension being arranged to be received within and retained by said oppositely disposed wedge-shaped walls.

2. A hammer for a centrifugal mill comprising a shank portion provided at one end with an opening for suspension, the opposite end of said shank being enlar ed in at least two dimensions, said enlarge end portion having a recess bounded on its opposite faces by wedge-shaped walls, the median line of.

said recess extending transversely to the direction of length of said shank and a tip member comprising a body portion extending at its oppositely disposed ends'to serve as tips and fur er comprising a wedgeshaped extension on one side of said body portion and disposed symmetrically relative to said tips, said wedge-shaped extension being arranged to be received within and re-- tained by said oppositely disposed wedgeshaped'walls, said enlarged en portion further having an extension projecting transversely to said wedge-shaped recess to thereby protect one of said tips.

In testimony whereof I have signed this specification this 21st da of July,'1924. GEO GE 1?. LUCAS. 

